There is known a drilling device including a fixing member fixable to a workpiece by means of an electromagnet and a cutting oil supply unit for supplying cutting oil to a cutting tool (see Japanese Unexamined Patent Application Publication No. 2006-061993).
A cutting oil supply unit in such a drilling device has an oil supply tank, which tends to collide with surrounding objects to be damaged in transportation and use of the drilling device. Therefore, it is required that the oil supply tank be disposed at a position where the oil supply tank is less likely to suffer such damage.
In a cutting tool disclosed in the above-mentioned Japanese Unexamined Patent Application Publication No. 2006-061993, an oil supply tank is configured to be disposed in a space between an electromagnetic fixing member and a cutting edge drive unit attached above the fixing member.    Patent Document 1: Japanese Unexamined Patent Application Publication No. 2006-061993    Patent Document 2: Japanese Unexamined Patent Application Publication No. 2007-132252